Warp tension control device for knitting machines



H. c. NOE

Jan. 11, 1955 WARP TENSION CONTROL DEVICE FOR KNITTING MACHINES 2Sheets-Sheet 1 Filed May 1, 1951 INVENTOR. BY Karma! /V56 ATTORNEY Jan.11, 1955 H. c. NOE 2,699,051

WARP TENSION CONTROL DEVICE FOR KNITTING MACHINES Filed May 1. 1951 2Shee ts-Sheet 2 II I n mm mllumlnlll lllllllllllllllllllllll mu gn vINVENTOR. filin CI 11 08 mzd.

ATTORNEY United States Patent WARP TENSION CONTROL DEVICE FOR KNITTINGMACHINES Harold C. Noe, Upper Montclair, N. J., assignor to KiddeManufacturing Co., Inc., Bloomfield, N. 1., a corporation of DelawareApplication May 1, 1951, Serial No. 224,000

13 Claims. (Cl. 66-86) The present invention relates to warp knittingmachines, and, more particularly, to improvements for supplying warpthreads to the knitting elements of such machines.

Warp knitting machines of the type with which the present invention isconcerned include a rotatably mounted warp beam for supplying the warpthreads, knitting elements operated to knit the warp threads intofabric, a fabric take-up roll, and devices for controlling the supplyand the tensioning of the warp threads. Preferably, the threads are letoff the beam at a rate in a predetermined relation to the rate at whichthe fabric is taken up, and the threads preferably are led to theknitting elements under a substantially uniform predetermined tension.

The present invention aims to accomplish the foregoing in connectionwith warp knitting machines of the high speed type adapted to knit 400or more courses per minute.

Accordingly, an object of the present invention is to provide a warpknitting machine wherein fluctuations in the tension of the yarn causedby the operation of the knitting elements are minimized.

Another object is to enable the warp threads to be let off continuouslyand supplied to the knitting elements under a desired uniform tensionregardless of the decrease in diameter of the warp beam.

Another object is to utilize the tension of the threads to control therate at which the threads are let off from the warp beam.

Another object is to arrange a pair of tension bars which cooperate witheach other to minimize fluctuations in tension of the warp threads.

Another object is to provide improved tension bar structure whichfacilitates the foregoing.

Another object is to increase the speed at which high speed warp)knitting machines can be operated by the provision of the foregoingimprovements.

A further object is to provide such improvements which are relativelysimple, practical and economical in construction and are reliable inoperation to assure continuous delivery of the warp threads at apredetermined rate and under a desired tension.

A still further object is to provide such improvements wherein thetension under which the warp threads are supplied is readily adjusted.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

In accordance with the present invention, the foregoing objects aregenerally accomplished by providing improvements comprising a variablespeed drive mechanism in operative connection with continuous drivemeans and the warp beam of the warp knitting machine for effectingcontinuous rotation of the beam to let off warp threads, means such as apivotally mounted tension bar over which the warp threads are adapted topass for compensating variations in the tension of the warp threads andfor controlling the drive mechanism to vary the speed at which the sameeffects rotation of the warp beam, and means such as a second tensionbar between the knitting elements of the machine and the first mentionedtension bar for partially compensating fluctuations in the tension ofthe warp threads.

Either or both of the tension bars may comprise a rail 2,699,051Patented Jan. 11, 1955 over which the warp threads are adapted to pass,a support, and a plurality of longitudinally spaced spring members eachsecured at one end to the support and carrying the rail at the free endthereof. Preferably, these members are generally C-shaped torsionsprings.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description, and

is shown in the accompanying drawing, forming a part of thespecification, wherein:

Figure 1 is a schematic end elevational view of a warp knitting machineillustrating the essential elements of the present invention.

Figure 2 is a fragmentary schematic front elevational view of themachine.

Figure 3 is a fragmentary sectional view taken substantially along theline 33 on Figure 2.

Referring to the drawings in detail, there is shown a portion of a warpknitting machine embodying the present invention with the conventionaldetails of such a machine being omitted for the purpose of schematicillustration. This machine as shown generally comprises a pair ofupright spaced apart end frames 10 and 11, a warp beam 12 rotatablymounted on the end frames, a drive shaft 14 such as the cam shaftsupported by the end frames, a variable speed drive mechanism 15 mountedon the end frame 11 adapted to be driven from the shaft 14 and in turneffect rotation of the warp beam, a pair of tension or flutter bars 16and 17 over which the warp threads pass in being supplied from the beamto the knitting elements 19 herein schematically indicated, and means 20for controlling the drive mechanism 15 in operative connection with thetension bar 17.

The tension bar 16, which is positioned between the tension bar 17 andthe knitting elements, comprises a support such as a rod or bar 21, arail 22 over which the warp threads pass, and a plurality oflongitudinally spaced apart spring members 24 for mounting the rail 22on the support. The ends of the support are mounted in bearings 25formed in the side frames 10 and 11, and are adjustably secured in adesired position therein by a set screw or the like (not shown).

The tension bar 17, which is positioned between the warp beam and thetension bar 16, comprises a support such as a rod or shaft 26, a rail 27over which the warp threads pass, and a plurality of longitudinallyspaced apart spring members 28 for mounting the rail 27 on thesupporting rod 26. The ends of the rod 26 are pivotally mounted inbearings or trunnions 30 provided on the side frames 10 and 11, and oneend of the rod is operatively connected with the variable speed drivemechanism 15 by the control means 20 as will be described in detailhereinafter.

A shaft 31, rotatably mounted between the side frames, is positionedbetween the warp beam and the tension bar 17 for guiding the warpthreads from the beam to this bar. I

As illustrated herein the spring members 24 and 28 are in the form offlat, substantially C-shaped torsion the type for example, known in thetrade as The Graham Variable Speed Transmission manufactured by GrahamTransmissions, Inc., Milwaukee, Wisconsin, and illustrated in BulletinNo. 514 distributed by the manufacturer. Since the construction of suchmechanisms is well known to those skilled in the art, detailedillustration and description thereof is believed to be unnecessary.Generally, such mechanisms comprise an input or driven shaft 36, anoutput or driving shaft 37, internal transmission elements (not shown)which are adjustable during operation of the mechanism for effecting achange of speed relation between the shafts, and a con- .trol arm 39 foradjusting these internal elements.

As illustrated herein, the shaft 36 is rotated by a sprocket 40connected by a chain 41 to a sprocket 42 on the shaft 14, and the warpbeam is rotated to let off the threads by a sprocket 44 connected by achain 45 to the sprocket 46 on the shaft 37. The control arm 39 isoperated by means 20 which comprise a rod 47 connected to an arm 48secured on the shaft .26 whereby rotative movement of this shaft, inresponse to variations in tension of the threads passing over thetension bar 17, effects a change in speed of the output shaft 37.

In order to maintain the warp threads let ofi from the beam under apredetermined tension, the tension bar 17 is urged in a clockwisedirection (as viewed) by a counterbalancing arrangement which comprisesa lever arm 50 secured to the rod 26, and weight 51 supported on thisarm. Preferably, the arm 59 is in the form of a frame having a rod 52for slidably mounting the weight thereon to provide for varying themovement exerted about the shaft or rod 26, and having a threaded shaft54 extending through a threaded bore of the weight and provided with ahand wheel 55 for rotating the same to adjust the position of theweight. While such a counterbalancing arrangement is shown only at oneend of the rod 26, it will be understood that a similar arrangement maybe provided at the other end of the rod (not shown) to more uniformlyapply the counterbalancing force.

In operation of the machine, the shaft 14 is rotated continuously toeffect continuous operation of the drive mechanism 15 which in turneffects continuous rotation of the warp beam to let off the warp thread.The Warp threads are guided under the shaft 31, over the rails 27 and22, and are received by the knitting elements 19 (Figure 3), the weight51 being adjusted on the arm 50 to apply a desired tension to thethreads.

As the knitting elements operate, the threads are alternately pulled andrelaxed to cause fluctuations in tension of the threads which arepartially compensated by the tension bar 16 which yields when thethreads are pulled due to yarn demand by the knitting elements andreturns when the threads are relaxed due to the resilience of the springmembers. In practice, it has been found that the tension bar compensatesabout 75% of the fluctuations in the tension of the threads in the zonebetween the knitting elements and the rail 22.

The tension bar 17 similarly yields and returns to compensate theremaining fluctuations in tension of the threads in the zone between therails 22 and 27 so that the fluctuation in tension of the threadsbetween the rail 27 and the warp beam is practically negligible.

However, as the warp beam decreases in diameter and is rotated at itsinitial speed to let off the threads, it cannot supply the constantthread demand of the knitting elements. Consequently, a decrease in thelet off rate causes an increase in the tension of the threads betweenthe beam and the tension bar 17. Since the rod 26 on which this tensionbar is mounted is pivotally supported, such an increase in tensioncauses the rod to be turned in a counterclockwise direction to effectoperation of the control element of the drive mechanism 15 whereby thewarp beam is driven at an increased rate to let off the threads at arate to meet the demand of the knitting elements and thus enable thecounterbalancing elements to cause the tension bar 17 to maintain theyarn under the desired predetermined tension. The deflection of therails 22 and 27 takes place so rapidly that alternate pulling andrelaxing of the threads do not effect material changes in the tensionthereof. Likewise, the let off rate is rapidly adjusted to maintain thesame substantially constant and in fixed relation to the demand of theknitting elements throughout the operation of the machine. The foregoingis accomplished while continuously rotating the warp beam whereby thisarrangement of elements enables the knitting machine to functionsmoothly and efiiciently to produce fabric of high quality at a highproduction rate. From the foregoing description, it will be seen thatthe present invention provides novel and useful improvements in knittingmachines which are simple and economical in construction and reliable inoperation. The elements constituting these improvements are extremelyrugged and can withstand long and continuous usage without wear orbreakdown, thereby eliminating frequent shut down of the machine forreplacement of parts or repair.

As various changes may be made in the form, construction and arrangementof the parts herein, without departing from the spirit and scope of theinvention and without sacrificing any of its advantages, it is to beunderstood that all matter herein is to be interpreted as illustrativeand not in any limiting sense.

I claim:

1. In a warp knitting machine of the class described, the combination ofdrive means, a warp beam, a support, a rail over which the warp threadsare adapted to pass, resilient means for mounting said rail on saidsupport. a pivotally mounted bar between said support and said beam, asecond rail over which the warp threads are adapted to pass, resilientmeans for mounting said second rail on said bar, a variable speed drivemechanism having a driven element in operative connection with saiddrive means and having a driving element in operative connection withsaid beam to effect rotation thereof, and means operatively connectedwith said pivotally mounted bar for controlling said drive mechanism.

2. A Warp knitting machine according to claim 1, wherein said support isfixed against movement.

3. A warp knitting machine according to claim 1, wherein both of saidresilient means are in the form of a plurality of C-shaped torsionsprings.

4. In a warp knitting machine of the class described, the combination ofdrive means, a warp beam, a pivotally mounted bar, a rail over which thewarp threads are adapted to pass, a plurality of C-shaped torsionsprings for mounting said rail on said bar, a variable speed drivemechanism having a driven element in operative connection with saiddrive means and having a driving element in operative connection withsaid beam to effect rotation thereof, and means operatively connectedwith said bar for controlling said drive mechanism.

5. A warp knitting machine according to claim 4, whereincounterbalancing means are connected to said bar.

6. In a warp knitting machine of the class described, the combination ofa Warp beam, a variable speed drive mechanism in operative connectionwith said beam for eflecting rotation of said beam to let off warpthreads, a pivotally mounted bar, a rail over which the warp threads areadapted to pass, a plurality of C-shaped torsion springs for mountingsaid rail on said bar, and means operatively connected with said bar forcontrolling said drive mechanism.

7. A warp knitting machine according to claim 6, whereincounterbalancing means are connected to said bar.

8. In a warp knitting machine of the class described, a warp tension barcomprising a rail over which the warp threads are adapted to pass, asupport, and a plurality of longitudinally spaced C-shaped springmembers each secured at one end to said support and carrying said railat the free end thereof.

9. A warp tension bar according to claim 8, wherein said rail isU-shaped in cross section and said members have U-shaped portions at thefree end thereof for mounting and securing said rail thereon.

10. A warp tension bar according to claim 8, wherein said support is afixed bar.

11. A warp tension bar according to claim 8, wherein said support is apivotally mounted bar.

12. A warp tension bar according to claim 8, wherein said support is arotatably mounted bar and means are provided for securing said bar infixed position.

13. In a warp knitting machine of the class described, the combinationof a warp beam, a variable speed drive mechanism in operative connectionwith said beam for etfecting rotation of said beam to let off warpthreads, a pivotally mounted bar, a laterally extending arm secured tosaid bar having a longitudinal groove, a weight having a threadedaperture and having a tongue in said groove adapted for slidablemovement along said arm, a threaded rod extending through said aperturein said weight for adjusting the position of said weight on said arm, amanual control for rotation of said threaded rod, a rail over which thewarp threads are adapted to pass, resilient means for mounting said railon said bar, and means operatively connected with said bar forcontrolling said drive mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 6Plunkett et a1 Aug. 28, 1945 Lambach Aug. 31, 1948 Young May 17, 1949Fuhrer Nov. 1, 1949 Clentimack Jan. 23, 1951

